Net Income Per Common Share	9 Months Ended
Sep. 30, 2013
Earnings Per Share [Abstract]
Net Income Per Common Share	Net Income Per Common Share For the purpose of computing diluted income from continuing operations and net income per common share, the weighted-average number of common shares outstanding is increased for the potential dilutive effects of stock-based incentive plans and convertible senior subordinated notes. For the purpose of computing diluted income from continuing operations and net income per common share, the weighted-average number of common shares outstanding was increased by 1,295,270 and 589,876 for the three-month periods ended September 30, 2013 and 2012, respectively, and 1,035,506 and 615,842 for the nine-month periods ended September 30, 2013 and 2012, respectively, to account for the potential dilutive effect of stock-based incentive plans and convertible senior subordinated notes. There were no adjustments to income from continuing operations or net income for the purposes of computing income available to common stockholders for those periods. The calculation of weighted-average diluted shares outstanding excludes all shares that would have been anti-dilutive. During the three-month periods ended September 30, 2013 and 2012, the Company excluded 27,300 and 367,428 stock options, respectively, from the calculation of weighted average diluted shares outstanding as the stock options would have been anti-dilutive. During the nine-month periods ended September 30, 2013 and 2012, the Company excluded 177,550 and 331,618 stock options, respectively, from the calculation of weighted average diluted shares outstanding as the stock options would have been anti-dilutive. The Company granted 130,600 stock options, 161,295 restricted stock unit awards and 135,055 performance share awards in February 2013 as part of its annual grant awards. All of the stock options and the restricted stock unit awards vest upon meeting certain service conditions. The restricted stock unit awards are included in basic average common shares outstanding as they contain nonforfeitable rights to dividend payments. The performance share awards are part of a long-term Relative Measure program, which is designed to assess the Company's performance relative to the performance of companies included in the Russell 2000 Index over the three-year term of the program ending December 31, 2015. The performance goals are independent of each other and based on three metrics: the Company's total shareholder return ("TSR"), basic earnings per share growth and operating income before depreciation and amortization growth (weighted equally). The participants can earn from zero to 250% of the target award and the award includes a forfeitable right to dividend equivalents, which are not included in the aggregate target award numbers. The fair value of the TSR portion of the performance share awards was determined using a Monte Carlo valuation method as the award contains a market condition. In the first quarter of 2013, the Board of Directors of the Company approved a Transition and Resignation Agreement (the "Agreement") for its former Chief Executive Officer (“Former CEO”) in connection with his resignation of the CEO role and his assumption of a Vice Chairman role. The Agreement provided that, in exchange for the Former CEO's delivery of an effective release of claims, his adherence to certain restrictive covenants, and the successful provision of transition services, including with regard to certain equity grants, the successful sale of the BDNA business, the Former CEO's outstanding equity awards are modified to increase the post-termination exercise period for stock options until the earlier of ten years from the date of grant or five years from the retirement date and made non-forfeitable all outstanding stock options, restricted stock unit awards and performance share awards that remained unvested on the day of his agreed to resignation date from the Company. The original vesting dates of the equity awards serve as the delivery dates and the performance metrics continue to apply to the performance share awards. The Company recorded $10,492 of stock compensation expense in the first quarter of 2013 as a result of the modifications. The 3.375% convertible senior subordinated notes due in March 2027 (the “Notes”) are convertible, under certain circumstances, into a combination of cash and common stock of the Company. The conversion price as of September 30, 2013 was approximately $28.31 per share of common stock. The dilutive effect of the Notes is determined based on the average closing price of the Company's stock for the last 30 trading days of the quarter as compared to the conversion price of the Notes. Under the net share settlement method, there were 286,205 and 128,594 potential shares issuable under the Notes that were considered dilutive for the three- and nine- month periods ended September 30, 2013, respectively. There were no potential shares issuable under the Notes for the three- and nine- month periods ended September 30, 2012 as the Notes would have been anti-dilutive.

Net Income Per Common Share

For the purpose of computing diluted income from continuing operations and net income per common share, the weighted-average number of common shares outstanding is increased for the potential dilutive effects of stock-based incentive plans and convertible senior subordinated notes. For the purpose of computing diluted income from continuing operations and net income per common share, the weighted-average number of common shares outstanding was increased by 1,295,270 and 589,876 for the three-month periods ended September 30, 2013 and 2012, respectively, and 1,035,506 and 615,842 for the nine-month periods ended September 30, 2013 and 2012, respectively, to account for the potential dilutive effect of stock-based incentive plans and convertible senior subordinated notes. There were no adjustments to income from continuing operations or net income for the purposes of computing income available to common stockholders for those periods.

The calculation of weighted-average diluted shares outstanding excludes all shares that would have been anti-dilutive. During the three-month periods ended September 30, 2013 and 2012, the Company excluded 27,300 and 367,428 stock options, respectively, from the calculation of weighted average diluted shares outstanding as the stock options would have been anti-dilutive. During the nine-month periods ended September 30, 2013 and 2012, the Company excluded 177,550 and 331,618 stock options, respectively, from the calculation of weighted average diluted shares outstanding as the stock options would have been anti-dilutive.

The Company granted 130,600 stock options, 161,295 restricted stock unit awards and 135,055 performance share awards in February 2013 as part of its annual grant awards. All of the stock options and the restricted stock unit awards vest upon meeting certain service conditions. The restricted stock unit awards are included in basic average common shares outstanding as they contain nonforfeitable rights to dividend payments. The performance share awards are part of a long-term Relative Measure program, which is designed to assess the Company's performance relative to the performance of companies included in the Russell 2000 Index over the three-year term of the program ending December 31, 2015. The performance goals are independent of each other and based on three metrics: the Company's total shareholder return ("TSR"), basic earnings per share growth and operating income before depreciation and amortization growth (weighted equally). The participants can earn from zero to 250% of the target award and the award includes a forfeitable right to dividend equivalents, which are not included in the aggregate target award numbers. The fair value of the TSR portion of the performance share awards was determined using a Monte Carlo valuation method as the award contains a market condition.

In the first quarter of 2013, the Board of Directors of the Company approved a Transition and Resignation Agreement (the "Agreement") for its former Chief Executive Officer (“Former CEO”) in connection with his resignation of the CEO role and his assumption of a Vice Chairman role. The Agreement provided that, in exchange for the Former CEO's delivery of an effective release of claims, his adherence to certain restrictive covenants, and the successful provision of transition services, including with regard to certain equity grants, the successful sale of the BDNA business, the Former CEO's outstanding equity awards are modified to increase the post-termination exercise period for stock options until the earlier of ten years from the date of grant or five years from the retirement date and made non-forfeitable all outstanding stock options, restricted stock unit awards and performance share awards that remained unvested on the day of his agreed to resignation date from the Company. The original vesting dates of the equity awards serve as the delivery dates and the performance metrics continue to apply to the performance share awards. The Company recorded $10,492 of stock compensation expense in the first quarter of 2013 as a result of the modifications.

The 3.375% convertible senior subordinated notes due in March 2027 (the “Notes”) are convertible, under certain circumstances, into a combination of cash and common stock of the Company. The conversion price as of September 30, 2013 was approximately $28.31 per share of common stock. The dilutive effect of the Notes is determined based on the average closing price of the Company's stock for the last 30 trading days of the quarter as compared to the conversion price of the Notes. Under the net share settlement method, there were 286,205 and 128,594 potential shares issuable under the Notes that were considered dilutive for the three- and nine- month periods ended September 30, 2013, respectively. There were no potential shares issuable under the Notes for the three- and nine- month periods ended September 30, 2012 as the Notes would have been anti-dilutive.